| 1. |
- Borisov, A. Y., et al.
(författare)
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On oxygen production by photosynthesis : A viewpoint
- 2018
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Ingår i: Photosynthetica. - : Institute of Experimental Botany. - 0300-3604 .- 1573-9058. ; 56:1, s. 44-47
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Tidskriftsartikel (refereegranskat)abstract
- In this brief communication we provide an estimate of the part of the incident solar energy used for oxygen evolution as well as the time, in years, needed for the generation of the present amount of molecular oxygen in the biosphere by photosynthesis on land and in the ocean. We find this to be ≈4,000 yr. We also find that the ocean produces 22% more oxygen than the land surface.
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| 2. |
- Tikhonov, K., et al.
(författare)
-
Quantification of bound bicarbonate in photosystem II
- 2018
-
Ingår i: Photosynthetica (Praha). - : Institute of Experimental Botany. - 0300-3604 .- 1573-9058. ; 56:1, s. 210-216
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we presented a new approach for quantification of bicarbonate (HCO3-) molecules bound to PSII. Our method, which is based on a combination of membrane-inlet mass spectrometry (MIMS) and O-18-labelling, excludes the possibility of "non-accounted" HCO3- by avoiding (1) the employment of formate for removal of HCO3- from PSII, and (2) the extremely low concentrations of HCO3-/CO2 during online MIMS measurements. By equilibration of PSII sample to ambient CO2 concentration of dissolved CO2/HCO3-, the method ensures that all physiological binding sites are saturated before analysis. With this approach, we determined that in spinach PSII membrane fragments 1.1 +/- 0.1 HCO3- are bound per PSII reaction center, while none was bound to isolated PsbO protein. Our present results confirmed that PSII binds one HCO3- molecule as ligand to the non-heme iron of PSII, while unbound HCO3- optimizes the water-splitting reactions by acting as a mobile proton shuttle.
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| 3. |
- Tikhonov, K., et al.
(författare)
-
Quantification of bound bicarbonate in photosystem II#
- 2018
-
Ingår i: Photosynthetica (Praha). - : Springer. - 0300-3604 .- 1573-9058. ; 56:1, s. 210-216
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we presented a new approach for quantification of bicarbonate (HCO3-) molecules bound to PSII. Our method, which is based on a combination of membrane-inlet mass spectrometry (MIMS) and O-18-labelling, excludes the possibility of "non-accounted" HCO3- by avoiding (1) the employment of formate for removal of HCO3- from PSII, and (2) the extremely low concentrations of HCO3-/CO2 during online MIMS measurements. By equilibration of PSII sample to ambient CO2 concentration of dissolved CO2/HCO3-, the method ensures that all physiological binding sites are saturated before analysis. With this approach, we determined that in spinach PSII membrane fragments 1.1 +/- 0.1 HCO3- are bound per PSII reaction center, while none was bound to isolated PsbO protein. Our present results confirmed that PSII binds one HCO3- molecule as ligand to the non-heme iron of PSII, while unbound HCO3- optimizes the water-splitting reactions by acting as a mobile proton shuttle.
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